Strategies to Mitigate Greenhouse Gas (GHG) Emissions from the Solid Waste Management Sector: A Case Study of Vavuniya, Sri Lanka

The waste sector is a substantial source of GHG emissions worldwide. Open dumping and internal combustion (IC) waste collection vehicles are significant sources of GHG emissions in Vavuniya. This research aims to estimate GHG emissions and recommend strategies to reduce emissions from the solid waste management sector. The IPCC methodology, considering Tier 1 estimation values based on default activity data, was used to estimate CH4 emissions from solid waste disposal sites. GHG emissions from collection vehicles were calculated based on IPCC mobile combustion recommendations. Three recommended strategies were considered based on demand, economic, and environmental feasibility and are expected to commence in 2025. According to current practices, open dumping generated 29.217 Gg of CO2 equivalent up to 2023, projected to rise by 37.8% by 2040. There will be a 57% decrease in open dumping-related GHG emissions by 2040 if composting is made mandatory for biodegradable waste, even though it produces emissions. Solar panels will be used to charge electric vehicles that will replace IC ones to cut emissions and fuel expenditures by 2025. The carbon sink reforestation program at the district level would need to begin in 2025 with an area of 161 hectares to sequester cumulative GHG emissions from composting dumpsites and fuel vehicles to achieve carbon neutrality by 2040. Investments from Vavuniya Carbon Sink Bonds (VCSB) on additional solar panels will ensure financial feasibility, having an internal rate of return of 23.18%. It paves the path to reducing GHG emissions, which is highly emphasized in the Nationally Determined Contributions, National Climate Change Policy, and waste management policy of Sri Lanka.


Introduction
Increasing population, thriving economy, urbanization, and growing living standards increase Municipal Solid Waste (MSW) generation in developing countries [1].Te inadequate management of MSW has emerged as a signifcant concern for the governments of several Asian and African nations [2].In developed countries, waste management is rigorously adhered to by established rules, laws, and policies.In developing countries, over 50% of waste is improperly discarded, contributing to GHG emissions and environmental damage [3].GHG is the primary driver of global warming and climate change, which disrupts the ecological balance [4].Te production of GHG from anthropogenic activities is a crucial worldwide concern regarding environmental health [5].Te MSW sector accounts for roughly 5% of the worldwide GHG budget [6].CH 4 , N 2 O, and CO 2 are the key reported GHG emissions from the waste sector [7,8].
It is essential to reduce the GHG emissions in the Solid Waste Management (SWM) system to achieve the statements addressed in the Nationally Determined Contributions (NDC) of Sri Lanka, which was submitted to the United Nations Framework Convention on Climate Change (UNFCCC) and National Climate Change Policy of Sri Lanka for the emission reduction [9,10].Over the last two decades, dumpsite rehabilitation eforts have improved waste segregation, collection, composting, and recycling [11,12].However, in the Vavuniya district, the conventional practices have been continued where there is no notable enhancement in SWM.Open dumping is carried out by the Local Authorities (LAs) of Vavuniya, which is considered a primary anthropogenic methane emission source and operates in four locations within the district [13].Fuel combustion from solid waste collection vehicles produces GHG emissions, causing global warming and air pollution [14].In this regard, the LAs have to make considerable eforts to reduce emissions at each LA level.Tis study aims to reduce GHG emissions in the SWM sector in Vavuniya by introducing composting as an alternative to the open dumping of biodegradable waste.Vehicle electrifcation was proposed; vehicles must be charged with solar panels instead of fuel to reduce emissions.A carbon sink reforestation program is suggested to ofset cumulative GHG emissions from the selective SWM activities.Moreover, technical and fnancial feasibility was undertaken to promote Vavuniya Carbon Sink Bonds (VCSB) to implement the project.

Methodology
2.1.Study Area.Te current study was conducted in the Vavuniya district, which is located in the Northern Province of Sri Lanka, and is a connecting hub of the North Central and Eastern Provinces of Sri Lanka.Five LAs that are functioning in the Vavuniya district, namely, Vavuniya Urban Council (VUC), Vavuniya South Tamil Pradeshiya Shaba (VSTPS), Vengalacheddikulam Pradeshiya Shaba (VCPS), Vavuniya North Pradeshiya Shaba (VNPS), and Vavuniya South Sinhala Pradeshiya Shaba (VSSPS) (Figure 1), whereas the LAs are further categorized into ward places presented in Table 1.Te highest population density in the VUC is nearly 2017 per sq.Km, whereas the lowest is VNPS [16,17].Four LAs provide solid waste management services in Vavuniya except for VSSPS.Mixed types of waste collection, limited recycling and recovery activities, and the open dumping of waste (Figure 2) have been considered as the major improper practices at the district level where anticipated environmental issues.

Data Collection.
Te study was based on a project to formulate solid waste management plans.Strategies to curtail GHGs, promote NDCs, and sustainable development goals are part of the plans.Preliminary data on SWM were gathered via a desk examination of secondary sources.Pertinent data and information on GHGs were extracted from a questionnaire survey that was designed under eight main topics: institutional structure, infrastructure development, research and development and education and training, social development, environmental management, resource allocation, monitoring and risk assessment, disaster management, and regulatory and law enforcement to collect comprehensive solid waste information [15].Te questionnaires were given to the LAs prior to the discussions on the information provided by the responsible ofcers and workers of the respective LAs.Te district engineer, fve secretaries of LAs, fve technical ofcers, fve public health inspectors, an environmental ofcer, seven supervisors, and ten workers provided data and information on solid waste compositions and quantities, waste collection vehicles, fuel consumptions, and disposal facilities.Moreover, the collection routes, frequencies, vehicle breakdowns, repair and maintenance, and information on collection and disposal crews were obtained.Site visits were made to quantify some of the data, like waste recycling, disposal amounts, and waste degradation in dumpsites.Te data and information obtained from the Vavuniya district were compared with those of other districts and provinces to determine the outliers by researching such variations.

Estimation of GHG Emissions.
Two approaches were considered: Business As Usual (BAU) and Recommended Strategies (RS) for GHG emission reduction.Te open dumping of degradable waste and solid waste vehicles are considered the key GHG emission sources at the LAs of Vavuniya.Te BAU was developed to estimate the GHG emissions as a continuation of current practices where emissions from open dumping and solid waste vehicles were considered.Instead of BAU, the economically and environmentally feasible Recommended Strategies "RS" were considered for the GHG emission reduction in the SWM sector in Vavuniya and is expected to commence in 2025, as presented in Table 2.
In the IPCC methodology, estimates of emissions and removals are categorized by sector.Tese sectors encompass homogeneous activities, sources, and sinks.Te sectors include Energy, which is divided into Fuel Combustion and Fugitive Emissions from Fuels; Industrial Processes and Product Use (IPPU); Agriculture, Forestry, and Other Land Use (AFOLU); Waste; and another category, which includes indirect emissions from nitrogen deposition from nonagriculture sources.Te IPCC methodology employs three tiers for emissions' estimation: Tier 1, Tier 2, and Tier 3. Tier 1 is the simplest approach, Tier 2 is intermediate, and Tier 3 is the most complex and data-intensive, typically providing the highest accuracy.Due to limited data availability, the Tier 1 method was adopted.Tis approach leverages readily available national or international statistics, default emission factors, and supplementary parameters, ensuring its feasibility for all countries [19].
In the solid waste management sector, the haulage vehicles belong to the IPPU sector.Although IPCC guidelines are geared towards determining key source categories of existing systems, they are essential and can address novel and transitional technologies for solar-driven systems.Hence, other criteria must be considered when determining key source categories that are not as easily accessed through a quantitative analysis.Tese criteria include the following.2 Scientifca

Mitigation Techniques and Technologies.
In the case of the study, the mitigation technologies are composting and replacing IC haulage vehicles with electric ones.Tere is certainty in identifying key source categories; thus, the Tier 1 methodology can be used because there are adequate data on waste dumping and the reductions of CH 4 emissions in the future with composting.Similarly, fuel consumption is known; thus, emissions from the past can be quantifed, and none will be in the future because of electric vehicles.

High Expected Emission Growth.
At the end of the IC and electric vehicle lifecycle, there are uncertainties in determining the emissions, and they could be key sources of emissions.Tis study assumes that both negate each other in terms of emissions because IC engines and most parts of the vehicles are discarded at the end of life in Sri Lanka.

High Uncertainty.
Tere is high uncertainty in using lithium-ion batteries because nonrecyclability becomes a key source of emissions since mining to extract lithium ore requires fossil fuels.Unless mining is done with electric vehicles and if there is a demand for secondary use of the batteries, such as for nonmovable energy storage, therefore, a Tier 2 application is needed to quantify much detailing of the lifecycle from extraction to recycling.

Unexpectedly Low or High Emissions.
Alternatively, less efcient lead-ion batteries are a low source of emissions.However, with increased demand at a lower energy density than lithium, it may become the key source of emissions.In the present-day context, lead-ion batteries can be easily produced and recycled using solar power and belong to Tier 1 estimation.[20,21].In Sri Lanka, 85% of the disposal sites are dumpsites [22].In Vavuniya, four dumpsites are used for solid waste disposal, considered the key source of GHG emission [15] in the waste sector.Te IPCC Methodology, considering Tier 1 estimation values based on default activity data, was used to estimate the CH 4 emission from Solid Waste Disposal Sites (SWDS) using equations (1)- (6).Te origin of biogenic CO 2 was not addressed in the waste sector.Other emitted gases from dumpsites, such as nonmethane volatile organic compounds (NMVOCs), nitrous oxide (N 2 O), nitrogen oxides (NO x ), and carbon monoxide (CO), can be negligible [23].
Equation ( 2) determines the remaining decomposable degradable organic carbon from solid waste at the end of year T, where the values for rate of the reaction content (k) and month of the reaction start (M) are 0.09 and 06 based on the IPCC waste model.Te decomposed DDOCmd (T) and accumulated DDOCmd (T) in the year of T are expressed by equations ( 3) and ( 4), where the total amount of DDOCm decomposed in year T is estimated using equation (5).
(3) Methane Generation at the Inventory Year T.
Finally, methane generation at the inventory year (T) was estimated in equation ( 6) from the decomposed waste, which is denoted as DDOCmdecomp (T), where the fraction of CH 4 (F) is 0.5.Te molecular weight ratio of methane/carbon is 16/12.
(4) Estimation of GHG Emissions in 2040.To estimate the GHG emission in 2040 at the dumpsites, equation (7) was used to calculate the estimated population in 2040 [24], where the solid waste generation and solid waste collection were estimated using equations ( 8)- (10).
Equation ( 7) estimates the population in 2040, representing the estimated population as P 2040 , P 0 as the initial population [7], e as the Euler number (2.7182), population growth rate r is 1.3, and t as the time in years [25].Equation (16) calculates Solid Waste Generation (SWG) in tons per day, with WG p denoting per capita per day waste generation where UC and PS have 0.6 kg and 0.4 kg, respectively [26].Solid waste collection (SWC) is estimated through equation ( 9), where WC ef represents Waste Collection Efcacy given in equation (10).Te proportion of solid waste compositions was assumed to be the same in 2023 and 2040 when the GHG emissions were determined using equations (1)-( 6).Composting is an economically feasible option, and it is in demand in this region [18] Gasoline solid waste collection vehicles Solar panels will be used to charge electric vehicles for solid waste collection and transportation Te initial investment cost is high.However, it is recommended to charge the electric vehicles by the solar panel, which will cut of future fuel expenses Vavuniya is located in the dry zone of Sri Lanka, where the solar radiation is enough throughout the year to charge the vehicles Emissions from dumpsites and vehicles before 2025 and the emissions from dumpsites and composting after 2025 Carbon sink reforestation program Even to stop the open dumping of degradable waste in 2025, GHG emissions will be produced until they reach saturation.
Reforestation is recommended to sequestrate already emitted GHG emissions dumpsites and vehicles.In addition, emissions from composting and open dumping will be after 2025 6 Scientifca

Solid Waste Transportation
Vehicles.Transportation of waste from its source to its destination for treatment or disposal contributes to GHG emissions.CO 2 , CH 4 , and N 2 O are emitted into the environment when waste transportation vehicles powered by fossil fuels such as diesel and gasoline are utilized [27,28].Diesel-powered vehicles have been used for collection and transportation in Vavuniya [18].According to IPCC recommendations [29], equation ( 7) was used to arrive at the expected total GHG emissions from the combustion of fossil fuels.Equation ( 8) is used for the energy required by vehicles during solid waste collection and transportation.
GHG emissions from diesel combustion (E T ) were computed in tons of CO 2 equivalent per year using equation (11), where FC Y is the fuel consumption in liters per year.Te diesel fuel thermal (D FT ) is 38.136 * 10 −6 TJ/L [30].Te IPCC's default fgure for EF CO2 is 74,100 kg/TJ, while EF CH 4 and EF N 2 O are 3.9 kg/TJ.Te CH 4 and N 2 O are comparable to 25 and 218 CO 2 [31].Te Energy Consumption of the Vehicles (ECv) was determined in kW per day using equation (12).Diesel Fuel Termal (D FT ) has a reference value of 38.136 MJ/L [30].Te FC d is Fuel Consumption per day in liters, converted into kWh and kW per day, assuming six running hours per day.
GHG emissions from solid waste collection vehicles from 2000 to 2023 were calculated based on equation ( 11) at each LA level, while the expected GHG emission in 2040 was calculated using equations (19) and (20).FR represents fuel requirement in liters per ton, while FC stands for fuel consumption measured in liters per day.
Te energy consumption was calculated using equation (12)  Vavuniya is an agriculture-based area with a demand for compost [17].Solid waste composting is the best option for GHG emission reduction when compared to open dumping [32].Te IPCC guideline includes CH 4 and N 2 O emissions estimation from composting based on equations ( 15) and (16).Biogenic CO 2 emissions are excluded [33].
Te M ow is the amount of organic waste (in Gg) processed in composting; EF is the emission factor in g of CH 4 /kg and g of N 2 O/kg of waste treated as 4 and 0.24, respectively, based on the IPCC default values.Total emission was estimated and compared in Gg of CO 2 equivalent where methane and N 2 O are 25 and 298 times higher than CO 2 [34].

Carbon Sink Reforestation Program (CSRP).
Trees have the capability of carbon sequestration, which aids in lowering the CO 2 levels in the atmosphere [35].Equation ( 17) was applied to determine the CO 2 sequestration potential (CS T ) in kilograms per hectare at the year T.
Te Number of Trees (NT) per hectare or the stocking density was considered to be 3100 trees per hectare [36].Moderate cumulative growth (CG T ) in kg carbon/tree at the year T multiplied by 44/12 to be converted as kg CO 2 sequestrated at the year T where the SF T is the moderate survival factor at the year T. Te default values CG T and SF T are obtained from the method for calculating carbon sequestration by the US Department of Energy [37].Equation (18) revealed that the Required Area (RA H ) in hectares was computed to neutralize the emission by 2040 at each LA and district level.
Te GHG emissions from solid waste disposal sites (GHGE SWDS ), composting (GHGE C ), and solid waste collection vehicles (GHGE V ) up to 2040, which is divided by the CS up to 2040 to get the required area in hectares at each LA level.

Electrifcation of Vehicles.
Te gasoline vehicles are intended to be substituted by electric vehicles by 2025 to reduce GHG emissions from solid waste collection vehicles.It can be expressed as NV is the number of vehicles needed for solid waste collection per day or the number of trips per day expressed in equation (19).EC v is the energy consumption of fuel vehicles (ECv) in kW per day, where Ef is the efciency of the electric vehicles, which is 0.6 [38].VC is the vehicle capacity in kWh, and the O p is the operation hours of the vehicle per day.Equation (20) was used to compute the required solar panels (R SP ) to charge electric vehicles, which were calculated using ECv in kW per day, the capacity of the solar panel in kWh, and the peak sunshine hours P SH is considered six hours per day.Scientifca 2.6.Technical and Financial Evaluation 2.6.1.Technical Evaluation.Te carbon footprint in the manufacturing of batteries is a concern.Terefore, it is crucial to select the best and most suitable one for recycling by considering the end-of-life option.Moreover, the selection of a suitable prime mover is important for the project.
2.6.2.Financial Evaluation.Most of the investments for activities in the LAs in the past relied on direct government initiatives through budgetary allocations and project-based activities by Non-Governmental Organizations (NGOs), International Agencies (INGOs), and foreign loans.LAs paid for some of the foreign-funded loans depending on the agreements.Also, LAs take loans from local government banks to purchase solid waste collection vehicles to be repaid with income from local tax and government allocations.In the present context, it is very difcult and challenging to get foreign-funded loans or grants and there are many restrictions on obtaining foreign exchange to purchase machinery and equipment.Nevertheless, there are many bilateral agreements to implement NDCs.It is understood that projects must be technically and fnancially feasible for both parties to agree on the required investment.It is also expected that the local party should invest to increase the viability of the project in terms of responsibility and sustainability.Terefore, each of the project components should contribute towards fulflling the NDCs.Tere should be sensible fnancial assumptions to make the project viable.Tey are (a) Te electrifcation of vehicles will increase and improve waste collection coverage.(b) Te project will not fail with 30% less income from solar power generation.(c) Te proposed system will feed the national grid with a net accounting agreement option.(d) Te Ceylon Electricity Board will not reduce the agreed tarif, unless to reach very low infation in the country.(e) Te value of the existing stock of IC engine vehicles is not accounted in the fnancial evaluation.(f ) Te establishment of the plant propagation laboratory and nurseries will generate income as Vavuniya Carbon Sink Bonds (VCSB).VCSB will be invested in solar power generation to pay back the loan and interest.People living or working in the Vavuniya district will be given priority in purchasing VCSB.Most importantly, home garden bondholders are the key stakeholders.Tey will beneft from the solar electrifcation project because the LAs will reinvest the profts in their household solar rooftops.Terefore, the adult population, assumed to be just over 90,000 being 50% of the population, will participate in the bond scheme.It will include large numbers from the urban sector.Te bonds can also be purchased to improve the waste collections and ofset the amount from taxes.
(g) Operational and fnancial statement of assumptions It is imperative to dwell on the statement of limiting conditions.Tey can be listed as (1) Te government approvals will be given to implement the project partnering with or without foreign collaboration.
(2) Te assets can be insured against all forms of disasters.
(3) Te project will be able to adhere to the project implementation timeline.(4) Te technical issues before commencing of the project can be solved.A small pilot study will be undertaken with the selected enterprises to evaluate the performances of the solar system.An independent body and interested fnancial institutions will be requested to participate in the evaluation.It can be a technical and fnancial evaluation team with stakeholders from the district, LA ofcials, and offcials of the Central Government.(5) Te expected expenditure and revenue are the basis for the fnancial projections reported.Tere are three capital cost components.Tey are (A) purchase of electric prime movers, (B) solar panels, and (C) establishment of plant propagation laboratory and nurseries.Apart from the capital costs, VCSBs are promoted to ofset the capital costs of (C) by way of additional solar panels to generate income for CS activities.Te later VCSB value is derived based on the ADB funded expenditure of USD 25 million for developing and improving 53,075 ha [39].Te present-day value is worked out based on a base infation rate of 4.5% in fossil fuel [40] increase compounded over 20 years.Te cost of solar panels is based on the present market price of USD 11,589 for 20 kW so that they can be installed in rooftops rather than have solar farms.According to the Federal Ofce of Energy Efciency and Renewable Energy, in the USA, the estimated scheduled maintenance costs for an electric vehicle average $0.06 cents per mile, while it is at $0.10 per mile for a conventional ICE-powered ride [41].Additionally, waste management vehicles need more cleaning.Terefore, a value of 25% of the fuel allocation is used as expenditure.Moreover, 3% of the revenue will be used to maintain PV panels and as administration costs.Te value of the rupee is expected to reduce by 5%, thus infation of 5%.Straight line depreciation over 20 years is used to have an economic life of 10% of the purchase price for equipment and 50% for solar panels.Te general insurance is 0.065% of the premium for machinery and equipment.Tere are many options for solar power generation agreements.Tis study considers a fxed revenue of USD 0.12 per kWh unit for the net accounting system.In a recent government circular, the tarif has been increased from USD 0.12 to 0.16 for promoting investments [42].It has been decided to have four streams of investments, notably, 8 Scientifca (i) Te excess generations from the solar panels (ii) Te allocation of fuel is used as an investment.
In the frst year of operation, there will be generations for nine months of the project year.
In the following years, for four years, solar installations from fuel allocations will continue for this fnancial evaluation.(iii) Te VCSB will be implemented, and the revenue generation will be efective after three months because of the envisaged installation timeline.Hence, there was power generation of nine months in the frst year.(iv) Te investment in the carbon sink will be in the form of seed and vegetative propagation, including tissue culturing to grow healthy trees and plants for short-and long-term revenue generations.Te VCSB stakeholders will participate in improving and developing home garden forests and community forests in the identifed lands in the Vavuniya district.Tey can outright pay for the bonds, or it could be through a fnancial institution that will hold the bonds until the sale of the short-term produce like green gram.Te project will provide the inputs for short-term income generation.
Te assessment of the feasibility was evaluated using the fnancial indicators: revenue expenditure, retained proft, operating cash fow, project cash fow, tax is not considered in this fnancial because of investing the profts in solar rooftops, return of investments (ROI), internal rate of return (IRR), and payback period.

Results and Discussion
Te solid waste generation, composition, and disposal of waste, the degree of economy, and the operation and management of each municipality can all be taken into consideration when selecting emission reduction strategies, such as raising the recycling rate, installing waste-to-energy conversion, benchmarking MSW, and establishing material recovery facilities for waste management.Tese strategies are crucial for growth planning and establishing goals for each municipality to lower emissions from the waste sector [38,[43][44][45].Te recommended emission reduction strategies were fnalized based on demand, economic viability, and environmental sustainability presented in Table 2.

GHG Emissions from Disposal Sites.
According to the current SWM practices, the GHG emissions were estimated up to 2040 from open dumpsites and the fuel combustion of vehicles.Four open dumpsites (Figure 1) are operated in the Vavuniya district to dispose of solid waste.Te anaerobic decomposition of degradable waste at the dumpsites produces gases, mainly CO 2 , CH 4 , and N 2 O, contributing to global warming [46].
VUC and VSTPS have disposed of mixed solid waste in the Pampaimadu dumpsite since 2000.Te VNPS has been operating dumpsites at two locations, such as Puttkulam and Sooduventhan, since 2016 to reduce transportation costs.In VNPS, there are two small towns located far away from each other where the population density is lower, which helped establish the disposal site in two locations.Te VCPS has been operating the Periyakattu dumpsite since 2009.According to the 2023 records, the solid waste composition has a huge degradable portion at each LA level, with VUC having 72%, VNPS 75%, VCPS 60%, and VSTPS 67%.It was the major source of GHG emissions from each dumpsite.
Te GHG emissions from SWDS were computed using the IPCC methodology of 2006 and 2019 refnement.Figure 3 illustrates DDOCm deposition, decomposition, and CH 4 emission from all dumpsites from 2011 to 2023.Te GHG emission from each dumpsite until 2023 was computed using the equations (1)-( 6) and presented in Table 3, along with the IPCC waste model and default values from IPCC guidelines for Tier (1) Emission Factor (EF).Table 3 demonstrates that the most signifcant contributor to GHG emissions is the Pampaimadu dumpsite.
To estimate the GHG emission in 2040 at the dumpsites, equation ( 7) was used to calculate the estimated population in 2040 [24], where the solid waste generation and solid waste collection were estimated using equations ( 8)-( 10) at each LA level addressed in Table 4. Te proportion of solid waste compositions was assumed to be the same in 2023 and 2040 when the GHG emissions were determined using equations ( 1)-( 6) expressed in Table 3.

GHG Emission from Solid Waste Collection Vehicles.
GHG emissions from solid waste collection vehicles from 2000 to 2023 were calculated based on equation (11) at each LA level, while the expected GHG emission in 2040 was calculated using equations ( 13) and ( 14), where abbreviations and the values are defned in Table 5. Te energy consumption was calculated using equation (12) based on the FC in 2040 and FC in 2023, displayed in Table 5.

Solid Waste Composting.
Solid waste composting is expected to be fully established by 2025 at each LA level instead of open dumping of degradable waste.Te solid waste collection was calculated using equations ( 7) and (10).Te solid waste composition was considered per the 2023 information.Te emissions from solid waste composting at each LA level were estimated using equations ( 15) and ( 16), shown in Figure 4.
First, SWDS emissions were projected to be reduced by implementing composting in 2025.Consequently, the predicted GHG emissions and reductions at each dumpsite in 2040 are outlined in Table 6, whereas Figure 5 depicts the GHG emissions from the dumpsites.

Electrifcation of Vehicles.
It was envisaged that diesel-powered vehicles would be replaced with 60 kWh electric tractors or compactors to reduce GHG emissions from solid waste collections.Te number of required tractors was calculated based on equation ( 19) with the Scientifca intention of charging the vehicles using 100 kWh solar panels, with the predicted electricity generations at each LA level determined using equation (20) presented in Table 7.

Carbon Sink Reforestation Program (CSRP). Te
Recommended Strategy (RS) anticipated to be implemented by 2025 is the introduction of composting and electric automobiles instead of open dumping of biodegradable and gasoline vehicles.Te acceptance of existing methods referred to as "Business as Usual" (BAU) is contrasted with the adoption of RS in Table 8.Te fndings indicate that RS, which is anticipated to lower 48.13 percent of total GHG emissions by 2040, would reduce dumpsite emissions by 31.13 percent.Te remaining cumulative emission is  anticipated to be neutralized by the fully grown trees in the reforested lands beyond 2040.Te needed area is computed using equations ( 11) and ( 12), shown in Table 8, for each LA level and district.

Technical Evaluation.
Tere is considerable debate on the use of electric vehicles because of the high carbon footprint in manufacturing batteries [47].Lead-acid batteries can be designed to be high power and are inexpensive, safe, recyclable, and reliable.However, low specifc energy, poor cold-temperature performance, and short calendar and lifecycle impede their use [48].Nevertheless, it is a viable option for small, slow-moving waste collecting tractors.Moreover, according to [49] "while nearly all -99% -of lead batteries are recycled, few lithium-ion batteries are recyclable, and the rate could be less than 5%.Most parts in electric vehicles are reusable, whereas the batteries are not designed to be recycled or reused.""Once in landflls, metals from the batteries can contaminate water and soil."Te global carbon footprint of the lithium-ion battery industry is projected to reach up to 1.0 Gt CO 2 -eq per year within the next decade.With material supply chain decarbonization and energy savings in battery manufacturing, a lower estimate of 0.5 Gt CO 2 -eq per year is possible.Moreover, there are improved techniques for recycling lithium-ion batteries [50][51][52][53][54], thus making the more advanced option a must for developing nations.Te second-hand market for batteries is relatively high, making the electric vehicles option very  [50,51].In Sri Lanka, licensed collectors have partnered with world-class battery recyclers in Belgium and Korea [53].

Financial Evaluation. Te capital costs as shown in
Table 9 amount to just over USD 600,000 with over 50% for solar generation panels.Te electric tractors are reasonably priced, and the replacement of IC will allow the best performance with greater comfort for the operator.Te need for compactors should be evaluated.Although the cost of establishing the nurseries is high, it is the backbone of the project.Te compost of urban biodegradable wastes with the required additions of inputs such as Arbuscular mycorrhizal fungi (AMF) [55] and biochar [56] will have a ready market in the plant nurseries.Te survival rate will be higher because of healthy plants grown in the nurseries for distribution.Additional investment is required in terms of VCSBs, amounting to USD 183,208.Te bonds will be used to purchase solar rooftop PVs that will generate power to make the project viable.Te VCSB is valued at USD 183,208 for 160 ha, which is USD 1145/ha, which exceeds the 2003 ADB project [39], having been compounded to give a value of USD 1135/ha.Each bond is valued at USD 2.00 derived from the maximum participation of the population in purchasing VCSB.Te loan repayment is given in Table 10 in the appendix at an interest rate of 10% and the duration of the loan is fve years.Te annual payment is USD 160,052.Te expenditure     6. Tere are many ways to overcome negative operating cash fow.One way is to extend the loan repayment period to six or seven years or have a grace period of one year for both interest and loan repayment.Tat saving can be invested on more solar panels to generate more revenue after installation.
In the event of 30% power generation reductions, the IRR reduces to 13.44%.It is above the borrowing rate; hence, the project is still viable and recovering in the seventh year.It will sustain an interest of 9.52% in the frst year's operating cash proft of USD 75,181.Such a scenario could be given to market long-term bonds, thus avoiding loans altogether or equity with VCSB.Te project can be described as an investment catalyst for the development of the country.Notably, the administrators have adequate confdence to launch sustainable development since it is very advantageous.Because the feasibility of electrifcation is based on the concept of the LAs to save on diesel while investing in solar power Scientifca generations, it will provide additional funds to purchase tractors and meet other expenditure.Solar income will be much above their need to invest in the Carbon Sink Reforestation Program.Certainly, it is a win-win situation for the waste generators, including bondholders, LAs, and the Central Government.LAs will not have to face the fuel increases every year crippling the budget, thus causing inevitable and uncontrollable mismanagement.Importantly, the project will never fail because the base infation rate tends to zero with the reduction in the use of fossil fuels [40].
Moreover, plant nurseries will continue to increase the supply of plants to meet the demand because of the increase in the value of tropical forests for medicinal and home garden (agriculture) productions [57].It is an attractive component in the investment cycle.Notably, Foreign Direct Investment (FDI) has an active role in the economic growth of the country [58].Unfortunately, a decline persists in the availability of FDI for developing countries [59].Moreover, the country is unable to repay debt-burdened loans.To make matters worse, the government is taking loans to buy fossil Te surplus capital investment on the environment is not new in the ancient civilization of Sri Lanka [60].Many have promoted it as sustainable solutions [61,62].As pointed out by [62], it is investing in nature-based solutions.

Conclusion
Tis study revealed that open dumping and solid waste transportation are signifcant sources of GHG emissions in the LAs of Vavuniya.Te Pampaimadu dumpsite, which is the largest, is afecting the populations living near the dump.Only those communities are aware of the present management system, but most of the populations are unaware of the constraints faced by the LAs.Inevitably, the impacts of solid waste on the environment and the implications of climate change and global warming are not explicitly known.
According to the IPCC recommendations, the integration of solid waste composting reduces nearly 57 percent of GHG emissions when compared to the BAU approach.Te introduction of electric vehicles cut the emissions from the solid waste transportation sector.Te initial investment is high.However, the fuel cost cut of when using electric vehicles.LAs are better placed to fulfl the NDC.Because the project is technically and fnancially feasible, catalyzing the process of achieving carbon net zero goals.Moreover, the investments for implementing CSRP can be directly derived from saving on fossil fuel use, which is also avoidance.Such climate actions are contrary to the belief that developing countries will take longer time to peak emissions and that emission reductions are undertaken based on equity and in the context of sustainable development while eradicating poverty, which are critical development priorities for many developing countries.Te RS is benefcial in achieving the national solid waste management policy statements aimed at reducing the amount of organic waste sent to landflls.NDCs often emphasize the importance of international cooperation and collaboration in achieving emission reduction goals.Te LAs can get support from international partners, organizations, and funding mechanisms to implement emissions reduction measures in the waste management sector.Te responsibilities of the LAs will be greater; thus, they need adequate support from the Provincial Council and the Central Government to implement the emission reduction strategic plan. -

Figure 1 :
Figure 1: Te (a) fgure shows the LAs and dumpsites in the Vavuniya district, the (b) fgure shows the location of the Vavuniya district, and the (c) fgure shows the surrounding districts of Vavuniya [15].

Figure 2 :
Figure 2: Solid waste fow in Vavuniya district.* Both recycling centers received very limited amount of waste ∼0.3 tons per day occasionally due to the limited space availability and labour force.

Table 2 :
Solid waste management approaches as "BAU" and "RS." based on the FC in 2040 and FC in 2023.

Table 4 :
Input parameters to calculate the GHG emission from SWDS.

Table 5 :
GHG emission from solid waste collection vehicles.

Table 6 :
GHG emission reduction at dumpsites compared to BAU.

Table 7 :
Required number of electric tractors and solar panels.

Table 8 :
Comparison of GHG emission and required area for tree plantation.Table11in the appendix.Te revenue increases from USD 131,531 to USD 255,756 in 2034 as shown in Table12in the appendix.Te working capital should be adequate for the sale of plants fromUSD 6,623with more than 50% increase in 10 years as shown in Table 13 in the appendix.Te proft and loss account given in Table14in the appendix indicate a gross proft of USD 106,512 in the frst year (2025) and at the end of the 10 th year USD 223,957.Te operating proft will increase by almost 60% at the end of 2030.Te retained proft will likely be USD 160,267 in fve years with a ROI of 21.39%.Te payback period is four years, as given in the forecast of project cash fow, Table15in the appendix.Tere is an increase of 48% in the Operating Cash Proft at the end of ten years.Nevertheless, the Operating Cash Flow is inadequate in the frst three years of operation.Hence, a grace period is needed for the loan repayment in the frst year, thus making it possible for the second year's loan instalment and interest payments.It can easily be accommodated since Project Cash Flow increases by 60% in the ffth year.Te project is viable with an IRR of 23.18%.Some fnancial variable indicators are shown in Figure

Table 9 :
Capital costs for establishing solar electrifcation of waste collections and carbon sink bonds.

Table 10 :
Schedule of loan capital and interest in USD.

Table 11 :
Summary of expenditures in USD.

Table 12 :
Revenue in USD.

Table 13 :
Working capital in USD.

Table 14 :
Projected proft and loss accounts in USD.

Table 15 :
Forecast of project cash fow in USD. to run the country.Notably, local banks can provide loans in Sri Lankan rupee but require foreign exchange to purchase the solar PVs and haulage vehicles.Bilateral trade agreements may be used for this purpose.Another more lucrative alternative is to tap the tourist sector to purchase VCSBs.Vavuniya carbon sink reforestation program will physically involve foreign bondholders to actively plant saplings named after them.Te local farmers purchasing those VCSBs will be the carers of those treasured saplings. fuel Figure 6: Financial variables indicate the changes with time.